Grinding machines

ABSTRACT

A grinding machine for grinding of valve seats in marine engines. The object of the invention is to provide a machine that is able to grind with sufficient accuracy for the pressures and temperatures at which marine engines operate and to provide a machine which at the same time is easy to apply and to operate. This has been achieved thereby that the machine is provided with a frame which is rotatable about a shaft adapted to be arranged in a valve stem bore and carries an arm which is mounted to be displaceable in an inclined track which is arranged in the frame and extends in a plane coinciding with the longitudinal direction of the shaft, the said arm carrying a holder for a grinding wheel and a driving motor associated with the said wheel, and also being displaced by means of a screw-threaded spindle which is mounted to be rotatable but axially nondisplaceable in the frame, the said screw-threaded spindle being provided at its upper end with a conveniently removable handle for turning the frame about the shaft, means being provided for converting a relative movement, brought about on rotation of the frame by means of the handle, between the frame and the screw-threaded spindle into a displacement of the arm, so that the grinding wheel, depending on the direction of rotation of the frame, is displaced either obliquely upwards and outwards or downwards and inwards in the direction from or towards the shaft.

United States Patent [72] Inventor Stig Oskar Christensson Malmo, Sweden [21] Appl. No. 322,470 [22] Filed May 7, 1969 I45] Patented July 27, 1971 [73] Assignee Chris-Marin AB Malmo, Sweden [32] Priority May 10, 1968 [33] Sweden [31 6318/68 [54] GRINDING MACHINES 4 Claims, 3 Drawing Figs.

[52] US. Cl 51/241A [51] Int. Cl .i..B24b 15/02 [50] Field ofSearch 51/241-0, 241.1,24l.l2

[56} References Cited UNITED STATES PATENTS 1,877,546 9/1932 Albee..... 51/241 1,877,782 9/1932 Albee 5l/24l Primary Examiner-Lester M. Swingle Alt0rneyl(ane, Dalsimer, Kane, Sullivan and Kurucz ABSTRACT: A grinding machine for grinding of valve seats in marine engines. The object of the invention is to provide a machine that is able to grind with sufficient accuracy for the pressures and temperatures at which marine engines operate and to provide a machine which at the same time is easy to apply and to operate. This has been achieved thereby that the machine is provided with a frame which is rotatable about a shaft adapted to be arranged in a valve stem bore and carries an arm which is mounted to be displaceable in an inclined track which is arranged in the frame and extends in a plane coinciding with the longitudinal direction of the shaft, the said arm carrying a holder for a grinding wheel and a driving motor associated with the said wheel, and also being displaced by means of a screw-threaded spindle which is mounted to be rotatable but axially nondisplaceable in the frame, the said screw-threaded spindle being provided at its upper end with a conveniently removable handle for turning the frame about the shaft, means being provided for converting a relative movement, brought about on rotation of the frame by means of the handle, between the frame and the screw-threaded spindle into a displacement of the arm, so that the grinding wheel,

depending on the direction of rotation of the frame, is displaced either obliquely upwards and outwards or downwards and inwards in the direction from or towards the shaft.

PATENTEnJuLzmn $3,594 9623 saw 2 OF 2 Fig.2

GRINDING MACHINES SUMMARY OF THE INVENTION The present invention relates to a grinding machine for the grinding of valve seats in marine engines. At the pressures and temperatures at which marine engines nowadays operate, gOOd sealing of valve seats is necessary, but owing to the temperatures which occur during combustion in the cylinder it is easy for burning-in phenomena or similar damage to occur at the valve seat, which consequently has to be reground frequently. Owing to the aforesaid higher pressure, this regrinding must be carried out with great precision, which may involve almost insurmountable difficulties under the conditions often prevailing on board a ship. It should also be possible to carry out this work in a relatively short time.

The present invention has as its object to provide a grinding machine suitable for the purpose indicated here. The grinding machine according to the invention consists of a frame which is rotatable about a shaft adapted to be arranged in a valve stem bore, and carries an arm which is mounted to be displaceable in an inclined track which is arranged in the frame and which extends in a plane coinciding with the longitudinal direction of the shaft, the said am comprising a holder for a grinding wheel and a driving motor associated therewith, and also being displaced by means of a screw-threaded spindle mounted to be rotatable but axially nondisplaceable in the frame, the said screw-threaded spindle being provided at its upper end with a conveniently removable handle for turning the frame about the shaft, means being provided for converting a relative movement between frame and screw-threaded spindle, brought about on rotation of the frame by means of the handle,-into a displacement of the arm, so that the grinding wheel, as a result of the direction of rotation of the frame, is displaced either obliquely upwards and outwards or downwards and'inwardsin the direction from or towards the shaft.

DESCRIPTION OF THE DRAWINGS In the accompanying drawings:

FIG. I shows a side view ofa grinding machine according to the present invention in a grinding position;

FIG. 2 shows on a larger scale a side view of the same device shown partly in section; and

FIG. 3 shows a plan view of this device corresponding to FIG. 2.

DESCRIPTION OF THE INVENTION The grinding machine of the present invention comprises a frame 1 which is mounted to be rotatable on a shaft 2 which itself is adapted to be inserted and arranged in a valve stem bore of a marine engine 3. The frame I carries an arm 4 mounted in an inclined manner, with a holder 5 for accommodating a grinding wheel 6 and a driving motor 7 associated therewith. A screw-threaded spindle 8 is also mounted in the frame I to be rotatable but axially nondisplaceable, its upper end being constructed as a stud 8' of noncircular cross section which corresponds to the lower end of a correspondingly shaped sleeve 9' of a handle 9 constructed as a socket wrench and adapted to be fitted on the stud 8, for turning the frame 1 about theshaft 2. At its lower end, the shaft 2 is provided with a connection 10 for a hose 11 leading to a source of compressed air (not shown). The compressed air is introduced through the shaft 2 and also through the hose 1] to the driving motor 7 for the grinding wheel 6.

In FIG. 2 the grinding machine is shown on a larger scale with its component parts: frame 1, arm 4, holder 5, and driving motor 7 for the grinding wheel 6. But in this figure the frame I is shown partly in section in order to illustrate how the screwthreaded spindle 8 extends down through the frame 1 and is screwed to a slide displaceable in the said frame. The slide 12 has an elongated aperture 13 into which a pin 14 fixed to the arm 4 engages, so that when the slide 12 is displaced vertically the arm 4 is also obliged to carry out a displacement movement in the inclined track associated therewith in the frame 1, the arm 4 with the holder 5, depending on the direction in which the frame 1 is turned by means of the handle 9, being displaced either obliquely upwards and outwards or obliquely downwards and inwards.

The frame 1 is also displaceable together with the grinding wheel 6 by an adjusting screw 15 relatively to the shaft 2 on a supporting angle 16 whose lower end is equipped with a bearing 17 whereby the entire grinding machine is supported, and is rotatable about the upper end of the shaft 2.

The regrinding of a valve seat with a grinding machine according to the present invention is carried out as follows. The grinding machine is introduced with its shaft 2 into the valve stem bore of the valve seat I8 to be reground and its grinding wheel 6 is made to abut on the valve seat. After the driving motor 7 has been started and the grinding wheel 6 consequently begins to rotate, the frame I is turned by means of the handle 9 placed on the stud 8 of the screw-threaded spindle, whereby a relative rotation occurs between the screwthreaded spindle 8 and the slide 12, and the slide 12 owing to be engaged by means of screw threading with the screwthreaded spindle 8 is displaced either upwards or downwards in a vertical along the said spindle, depending on the direction of rotation of the frame 1. Owing to the engagement of the pin 14 in the aperture 13 of the slide 12, the arm 4 is displaced in the inclined track associated therewith in the frame 1 and the grinding wheel 6 is displaced along the valve seat 18, regrinding the said seat.

However, it is often desirable to enable the frame I to be rotated about its axis but without having to displace the grinding wheel radially, for example, for regrinding the plane valve seat portion 19. For this reason a conveniently rotatably mounted pin 20 for the handle 9 has been arranged at the holder 5. On rotation of the grinding machine about its shaft 2 by means of the handle 9 fitted on to the pin 20 at the holder 5, the rotating grinding wheel will be moved in an are about the center point of the valve seat without being radially displaced.

The present invention provides a versatile grinding machine which is suitable more particularly for rapid and precise regrinding-more especially of valve seats, and as a particular advantage there may be mentioned the possibility of surmounting the frame 1 on the shaft 2 by means of a supporting angle 16 that the grinding wheel 6 can be displaced to such an extent in the direction of the center of the valve seat that its inner edge can be taken almost up to or even over the center. Thus, with the outer edge of the grinding wheel 6, regrinding can be carried out much nearer to the center than has been possible hitherto.

The invention is only to be regarded as an example and can be modified constructionally within the framework of the following claims.

What I claim is:

I. A grinding machine, more particularly for the grinding of valve seats in marine engines, wherein the improvement comprises a frame which is rotatable about a shaft adapted to be arranged in a valve stem bore andcarries an arm which is mounted to be displaceable in an inclined track which is arranged in the frame and extends in a plane coinciding with the longitudinal direction of the shaft, the said arm carrying a holder for a grinding wheel and a driving motor associated with the said wheel, and also being displaced by means of a screw-threaded spindle which is mounted to be rotatable but axially nondisplaceable in the frame, the said screw-threaded spindle being provided at its upper end with a conveniently removable handle for turning the frame about the shaft, means being provided for converting a relative movement, brought about on rotation of the frame by means of the handle, between the frame and the screw-threaded spindle into a displacement of the arm, so that the grinding wheel, depending on the direction of rotation of the frame, is displaced either obliquely upwards and outwards or downwards and inwards in the direction from or towards the shaft 2. A grinding machine according to claim 1, wherein the improvement comprises movement-converting means that consist of a slide engaging by means of screw threading with the screw-threaded spindle in order to be displace in a vertical sense on rotation of the aforesaid screw-threaded spindle in an aperture in the frame, and that the arm is provided with a pin engaging in a track in the slide.

3, A grinding machine according to claim I. wherein the improvement comprises a holder that is provided with a pin for 

1. A grinding machine, more particularly for the grinding of valve seats in marine engines, wherein the improvement comprises a frame which is rotatable about a shaft adapted to be arranged in a valve stem bore and carries an arm which is mounted to be displaceable in an inclined track which is arranged in the frame and extends in a plane coinciding with the longitudinal direction of the shaft, the said arm carrying a holder for a grinding wheel and a driving motor associated with the said wheel, and also being displaced by means of a screw-threaded spindle which is mounted to be rotatable but axially nondisplaceable in the frame, the said screw-threaded spindle being provided at its upper end with a conveniently removable handle for turning the frame about the shaft, means being provided for converting a relative movement, brought about on rotation of the frame by means of the handle, between the frame and the screw-threaded spindle into a displacement of the arm, so that the grinding wheel, depending on the direction of rotation of the frame, is displaced either obliquely upwards and outwards or downwards and inwards in the direction from or towards the shaft
 2. A grinding machine according to claim 1, wherein the improvement comprises movement-converting means that consist of a slide engaging by means of screw threading with the screw-threaded spindle in order to be displace in a vertical sense on rotation of the aforesaid screw-threaded spindle in an aperture in the frame, and that the arm is provided with a pin engaging in a track in the slide.
 3. A grinding machine according to claim 1, wherein the improvement comprises a holder that is provided with a pin for cooperation with the handle so that the holder with the grinding wheel can be pivoted about the shaft of the frame without being displaced in the radial sense.
 4. A grinding machine according to claim 1, wherein the improvement comprises a frame that is radially adjustable relatively to the grinding wheel on a supporting angle which is provided with a bearing and whereby the entire grinding machine can be rotated about the upper end of the shaft. 